SICP 問題 2.23
(define (for-each proc items) (cond ((null? items) 'done) (else (proc (car items)) (for-each proc (cdr items)))))
gosh> (for-each (lambda (x) (newline) (display x)) (list 57 321 88)) 57 321 88done
(define (for-each proc items) (cond ((null? items) 'done) (else (proc (car items)) (for-each proc (cdr items)))))
gosh> (for-each (lambda (x) (newline) (display x)) (list 57 321 88)) 57 321 88done